[chris_seven]

Tadd,

Couple of points I forgot - I don't think it is realistic to put shims under the lash cap you really need to make them the correct size.

As regard 9mm bore Top Hats I can buy the following off the shelf:

Internal Diameter: 9mm
External Diameter: 13mm
Internal Depth: 3mm
Workable Depth: 1.5mm-5mm

They are a bit pricey at about $10 each but manufactured by a very reputable supplier and of excellent quality.

The thing that frustrates me about the 906/RSR Rocker is just the price.

I can buy them in the UK but at about $450 + Sales Tax each - which is crazy.

They are new parts and are reasonable quality.

For less than the cost of one set I could buy the forging tool and 250 heat treated 4340 forgings

Maching, grinding and finishing the rocker in batches would also be very cost effective. I have contarcted this work to a local camshaft manufacturer that has been making 'billet' rockers for racing motocycles for 20 years.

I have the entire process lined up for the adjustable rocker so doing the 'solid'rocker would be quite easy.

I understand your comments about frictional losses and developed a firction test system at Cosworth in the 3.0 litre V10 days and at 19000 rpm when the spark turned out the friction was around 100 Nm measured at the crank.

When you consider that the peak torque of this motor was only 300Nm chasing friction was more beneficial than thermodynamics at that time.

I am not sure, however, if it is very cost effective at 8000rpm unless you are chasing every fraction of a horsepower on a Nascar motor or similar.

I will try to find out cam friction levels in current F1 engines as I don't have any individual component data. ( I witnessed the first stage of the test programme but was kicked out as they started dismantling and making component by component measurements)

Certainly friction at the nose of the cam can be relatively high as velocity is low and tends to zero and asperities can tend to lock (sticking friction?)

I am sure DLC will help this but I think this is a reult of the high level of surface finish used before the coating.

I think a process such as Isotropic Superfinishing would also work very well and may be easier.

I would think you will need the same standard of finish on the rocker as well.